Area Forecast Discussion
Issued by NWS Northern Indiana

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000
FXUS63 KIWX 241745
AFDIWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1245 PM EST MON NOV 24 2014

.SYNOPSIS...
ISSUED AT 1040 AM EST MON NOV 24 2014

EXTREMELY WINDY CONDITIONS ARE EXPECTED TODAY AS A STRONG STORM
SYSTEM AND COLD FRONT MOVES THROUGH THE GREAT LAKES REGION. RAIN SHOWERS
WILL CHANGE TO SNOW SHOWERS AS COLDER AIR SURGES INTO THE AREA...WITH
A POTENTIAL OF LIGHT SNOW ACCUMULATIONS ACROSS PORTIONS OF
NORTHWEST AND NORTH CENTRAL INDIANA AND SOUTHERN LOWER MICHIGAN
THROUGH EARLY TUESDAY. TEMPERATURES WILL CONTINUE TO DROP SHARPLY
THROUGH THE 30S AS THE COLD FRONT MOVES THROUGH. LOW TEMPERATURES
TONIGHT WILL DROP INTO THE MID TO UPPER 20S.

&&

.UPDATE...
ISSUED AT 1040 AM EST MON NOV 24 2014

INTENSE MESOVORT IN LEADING DRY SLOT ACRS CENTRAL CWA MOVG RAPIDLY
NWD. MIXDOWN ALREADY BRINGING G50 KTS AT KFWA. POWER OUTAGES
EXPECTED...MORE TREES/BRANCHES/SEMIS OR LARGE VEHICLES BLOWN OFF
ROADWAYS PROBABLE. UPG SERN HALF CWA TO HIGH WIND WARNING WHERE
HIEST /9.5-10.5 C/KM LAPSE RATES TO ENVELOP WARNED REGION BTWN
18-21 UTC TIMEFRAME COINCIDENT WITH MAX MOMENNUM XFER OF 45-60 KT
900-850MB LAYER FLOW ANTICIPATED WITH CROSS ISALLOBARIC COUPLET
ON ORDER OF 10 MB/3HRS.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 409 AM EST MON NOV 24 2014

MAIN FORECAST CONCERNS WILL CONTINUE TO CENTER ON VERY WINDY
CONDITIONS TODAY...CONVECTIVE POTENTIAL THIS MORNING...AND PRECIP
TYPE TRENDS THIS AFTERNOON ALONG WITH SOME LIGHT SNOW ACCUMULATIONS.

LEAD UPPER LEVEL SHORT WAVE IS BEGINNING TO LIFT NORTHWARD ACROSS
EXTREME NORTHERN INDIANA AND SOUTHERN LOWER MICHIGAN THIS
MORNING...WITH A LULL IN THE GREATER RAIN COVERAGE EXPECTED OVER THE
NEXT FEW HOURS. THIS LULL WILL BE SHORT LIVED AS ANOTHER VORT MAX
ACROSS SOUTHEAST MISSOURI SWINGS INTO THE OHIO VALLEY THIS MORNING.
ALREADY BEGINNING TO SEE A FEW REPORTS OF SUSTAINED WINDS IN THE 25
TO 35 MPH RANGE WITH A FEW GUSTS TO 40 TO 45 MPH ACROSS NORTHWEST
OHIO. THESE STRONGER GUSTS APPEAR TO BE CO-LOCATED WITH STRONG
ISALLOBARIC GRADIENT MARKING NORTHEAST DEPARTURE OF CORE OF STRONG
PRESSURE FALLS ACROSS SOUTHEAST ONTARIO. EXPECTING THESE WINDS TO
SUBSIDE A BIT OVER THE NEXT HOUR AS THE STRONGER ISALLOBARIC
GRADIENT SHIFTS NORTHEAST.

AN INCREASE IN SHOWERS IS EXPECTED AGAIN FROM THE SOUTHEAST IN
ASSOCIATION WITH THE SOUTHEAST MISSOURI VORT MAX. A BIT MORE
INSTABILITY IS EXPECTED WITH THIS VORT MAX AS WEAK MID LEVEL COLD
ADVECTION BEGINS TO IMPINGE ON LOW LEVEL THERMAL RIDGING ACROSS THE
AREA. 00Z NAM STILL DEPICT MUCAPES ON THE ORDER OF 100-300 J/KG
WORKING ACROSS THE AREA THIS MORNING BEFORE STRONG LOW LEVEL COLD
ADVECTION PUSH WITH THE FRONT. EXPECTING A SHARP INCREASE IN SFC
WIND SPEEDS ONCE AGAIN BY THE 12Z-15Z TIMEFRAME AS MAIN LOW LEVEL
THERMAL RIDGE SHIFTS ACROSS EXTREME NORTHEAST INDIANA/NORTHWEST
OHIO PROMOTING SOME BETTER MIXING. NAM/GFS/RAP BUFFER SOUNDINGS
ALL POINTING TO AT LEAST THE POTENTIAL OF MIXING DOWN SOME 50+ MPH
WIND GUSTS ACROSS FAR EASTERN PORTIONS OF THE AREA THIS
MORNING...PARTICULARLY ACROSS NORTHWEST OHIO COUNTIES. THIS THREAT
SHOULD MAXIMIZE IN THE 16Z-20Z TIMEFRAME WHEN STRONGER ISALLOBARIC
GRADIENT SHIFTS ACROSS THESE LOCATIONS. WITH POTENTIAL OF SHALLOW
CONVECTION ALSO WORKING ACROSS THE AREA THROUGH MIDDAY...WILL HAVE
TO WATCH FOR ANY ISOLATED HIGHER WIND GUSTS ASSOCIATED WITH
ENHANCED LOCALIZED MIXING OF STRONGER WINDS ALOFT. STILL
EXPECTING GUSTS INTO THE 40 TO 45 MPH RANGE ACROSS THE REMAINDER
OF THE AREA...PERHAPS A BIT MORE MARGINAL IN NATURE ACROSS THE
NORTHWEST. HAVE OPTED TO MAINTAIN GOING WIND ADVISORY...WITH A
MENTION OF 50+ MPH WIND GUSTS AS A POSSIBILITY ACROSS THE FAR
EAST THIS MORNING/EARLY AFTERNOON. A SLIGHT EXTENSION IN TIME FOR
THE WIND ADVISORY MAY BE NEEDED PAST 00Z ACROSS PORTIONS OF THE
AREA...BUT CONFIDENCE IS LOW AT THIS TIME.

IN TERMS OF PRECIP...BEST SYNOPTIC FORCING TO PERSIST ACROSS
NORTHWEST LOCATIONS TODAY AS NEXT VORT MAX DIGS ACROSS MID MS VALLEY
AND EVENTUALLY LIFTS NORTHEAST INTO THE WESTERN GREAT LAKES. BETTER
DEFORMATION FORCING BY THIS EVENING STILL APPEARS TO SET UP
NORTHWEST OF THE LOCAL AREA...ALTHOUGH COMBINATION OF LINGERING
SYNOPTIC FORCING AND WEAK LAKE ENHANCEMENT MAY SUPPORT MINOR
SNOW ACCUMULATIONS ACROSS PRIMARILY SOUTHWEST LOWER MICHIGAN
TONIGHT INTO TUESDAY. ONLY TWEAK TO WEATHER GRIDS THIS MORNING WAS
FOR JUST A SLIGHTLY SLOWER EVOLUTION TO SNOW SHOWER PTYPE THIS
AFTERNOON...BUT OTHERWISE NATURE OF PREVIOUS GRIDS REMAINS INTACT.
MORNING HIGHS MAY EVEN REACH 60 OR LOWER 60S ACROSS THE EXTREME
SOUTHEAST BEFORE SHARP LOW LEVEL COLD ADVECTION SETS IN LATER THIS
MORNING WITH TEMPERATURES FALLING THROUGH THE 40S ACROSS THE
AREA...AND INTO THE MID 30S ACROSS THE WEST.

&&

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 409 AM EST MON NOV 24 2014

AN UNWELCOMED RETURN TO COLD TEMP ANOMALIES THE PRIMARY WX STORY
MID-LATE WEEK AS ADDITIONAL EAST PACIFIC JET ENERGY HELPS REINFORCE
A RATHER DEEP EASTERN CONUS UPPER TROUGH. PIVOT THROUGH OF MID LVL
DEFORMATION AXIS/DEEPER SATURATION TUE AM AND ADDED MOISTURE FLUX
OFF LAKE MI WILL KEEP SNOW SHOWER/FLURRIES/CLOUDS AROUND TUESDAY
(MAINLY NORTH). MINOR ACCUMS POSSIBLE ALONG/NORTH OF THE TOLL ROAD
GIVEN LAKE-8H TEMP DIFFERENTIALS INTO THE UPPER TEENS/WESTERLY
FLOW...WITH LOW INVERSION HEIGHTS NEAR 5-6 KFT/SHALLOW DGZ LIMITING
FACTORS FOR MORE SUBSTANTIAL ACCUMS. THE NEXT CHANCE FOR LIGHT SNOW
WILL COME LATER WEDNESDAY-WEDNESDAY NIGHT AS CLIPPER SYSTEM DROPS SE
IN FLATTENING NW FLOW. LAST SEVERAL MODEL CYCLES HAVE TRENDED TOWARD
A MORE SOUTHERLY TRACK INTO THE MID MS/WESTERN OH VALLEYS PLACING
OUR SOUTHWESTERN ZONES IN A BETTER SPOT FOR A PERIOD OF LIGHT SNOW.
RENEWED SHOT OF MODIFIED POLAR AIR IN VEERED WNW FLOW IN WAKE OF
THIS WAVE SHOULD ALLOW LAKE EFFECT EFFECT SNOW SHOWERS/FLURRIES TO
DEVELOP ON THANKSGIVING. COULD SEE SOME ACCUMULATIONS/IMPACTS IN
FAVORED WNW FLOW ZONES AS 700 MB DELTA T`S PLUMMET INTO THE LOW-MID
20S AND INVERSION HEIGHTS INCREASE TO NEAR 10 KFT PER LATEST FCST
SOUNDINGS.

RELAXATION OF HEIGHT FIELD LATE IN THE WEEK/NEXT WEEKEND WITH POLAR
JET/LOW LEVEL BAROCLINIC ZONE POTENTIALLY LIFTING NORTH OF THE
FORECAST AREA SHOULD ALLOW MILDER/MORE SEASONABLE AIR TO BRIEFLY
ADVECT IN BY AROUND FRIDAY NIGHT-SATURDAY. A NARROW BAND OF LIGHT
SNOW MAY ACCOMPANY THIS WARM ADVECTION SURGE AROUND
FRIDAY...ALTHOUGH MODEL CONSENSUS SUGGEST MUCH BETTER CHANCES NORTH
OF THE FA. OTHERWISE....RAISED HIGHS CONSIDERABLY ON SATURDAY GIVEN
EXCELLENT 00Z MODEL AGREEMENT.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1237 PM EST MON NOV 24 2014

PRONOUNCED PRESSURE GRADIENT WILL PERSIST THROUGH 01Z WITH WINDS
GUSTING TO OVER 40 KNOTS. SUSTAINED WINDS OF 25 TO 35 KNOTS WILL
LINGER THROUGH 04Z BEFORE ABATING AS HIGH PRESSURE SHIFTS EASTWARD
AND THE LOW DEEPENS OVER THE EASTERN GREAT LAKES.

IN THE NEAR TERM THE BOUNDARY LAYER IS SATURATED IN THE
DEFORMATION AXIS OVER THE SOUTHERN GREAT LAKES AND THIS HAS
TURNED...OR WILL TURN LIQUID PRECIP TO FROZEN QUICKLY. LIGHT SNOW
WILL LINGER THROUGH THE FIRST 12 HOURS HOURS OF THE FORECAST
PERIOD...AND CIGS WILL REMAIN AT IFR WITH ISOLD LIFR CONDITIONS.

AS THE DEFORMATION AXIS SHIFTS NORTH AND EAST CONDITIONS EXPECTED
TO GRADUALLY IMPROVE...HOWEVER EXPECT TO SEE IFR CIGS PERSISTING
THROUGH END OF THE FORECAST PERIOD.


(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 642 AM EST MON NOV 24 2014

A STRONG UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT WILL
CONTINUE TO PRODUCE UNSETTLED WEATHER ACROSS NORTHERN INDIANA
TODAY. AFTER A BRIEF LULL IN RAIN SHOWERS OVERNIGHT...NEXT UPPER
LEVEL SHORT WAVE WILL BRING A PERIOD OF RAIN SHOWERS TO TERMINALS
THROUGH AT LEAST MID MORNING. SOME INCREASING INSTABILITY WITH
THIS SHORT WAVE WILL LEAD TO VERY SMALL PROBABILITIES OF THUNDER AT
TERMINALS. POTENTIAL AT ANY ONE POINT IS TOO SMALL TO MENTION FOR
THE 12Z TAFS. BIGGER STORY CONTINUES TO BE INCREASING WINDS THIS
MORNING. STRONG SOUTH/SOUTHWEST WINDS ARE EXPECTED TO DEVELOP JUST
IN ADVANCE OF THE COLD FRONT THIS MORNING AT KFWA...WITH STRONG
SOUTHWEST WINDS DEVELOPING AT BOTH TERMINALS TOWARD THE 15Z
TIMEFRAME IN ASSOCIATION WITH THE COLD FRONT. SOUTHWEST GUSTS TO
40 TO 45 KNOTS ARE POSSIBLE AT KFWA...WITH AROUND 35 KNOTS AT
KSBN. WIND GUSTS SHOULD SUBSIDE THIS EVENING AS THE STRONG LOW
PRESSURE AREA WITH THIS SYSTEM CONTINUES TO LIFT OUT. THE MORE
PROLONGED PERIOD OF SYNOPTIC FORCING IS STILL EXPECTED AT
KSBN...WHERE RAIN SHOWERS WILL CHANGE TO SNOW SHOWERS THIS
AFTERNOON...WITH LITTLE OR NO SNOW ACCUMULATION. MAIN UPPER TROUGH
MOVING THROUGH TONIGHT COMBINED WITH LAKE ENHANCEMENT WILL PROVIDE
CONTINUED SCATTERED SNOW SHOWERS...ALTHOUGH BETTER CHANCE OF
LIGHT SNOW ACCUMULATIONS SHOULD BE LOCATED NORTH OF KSBN.


&&

.IWX WATCHES/WARNINGS/ADVISORIES...
IN...HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR INZ007>009-
     016>018-022>027-032>034.

     WIND ADVISORY UNTIL 7 PM EST /6 PM CST/ THIS EVENING FOR
     INZ003>006-012>015-020.

MI...HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR MIZ081.

     WIND ADVISORY UNTIL 7 PM EST THIS EVENING FOR MIZ077>080.

OH...HIGH WIND WARNING UNTIL 7 PM EST THIS EVENING FOR OHZ001-002-004-
     005-015-016-024-025.

LM...GALE WARNING UNTIL 4 AM EST TUESDAY FOR LMZ043-046.

&&

$$

UPDATE...MURPHY
SYNOPSIS...MURPHY
SHORT TERM...MARSILI
LONG TERM...STEINWEDEL
AVIATION...LEWIS


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